Bobbin holder

Abstract: A bobbin holder mounted on a yarn winding machine which bobbin holder comprises a plurality of chucking members (12A-12L) disposed at an outer periphery of a holder (3), the chucking members being expanded radially outwardly so as to chuck an inner side of a cylindrical bobbin coaxially inserted onto the holder when they are longitudinally compressed and the chucking members releasing the bobbin when they are moved radially inwardly, portions on the holder for disposing the chucking members are formed in a concave (3a-3l), a part of the chucking members is inserted into the concave.

Description: BRIEF DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a bobbin holder onto which a cylindrical bobbin is inserted and held thereby, which bobbin holder is mounted on a winding machine wherein a yarn is wound onto the bobbin. The bobbin holder of the present invention is especially suitable for a winding machine for winding a spun synthetic yarn such as a polyester or polyamide yarn at a speed, for example, of several thousands m/min. Description of the Prior Art Recently, there is a tendency in a yarn winding apparatus that the diameter of a bobbin is reduced. Accordingly, the diameter of a bobbin holder is also reduced, and at the same time the length of the bobbin holder becomes long as its winding speed increases. Recently developed bobbin holders mounted on such a winding machine are disclosed, for example, in Japanese Utility Model Applications Laid-open No. Sho 60-43667 and No. Sho 60-1766 and Japanese Patent Application Laid-open No. Sho 55-123847. Since a chucking member is inserted onto an outside of a supporting shaft or a holder in such conventional bobbin holders, the outer diameter of the shaft or the holder is equal to a size which is obtained from an inner diameter of the bobbin after the necessary size for the chucking member is excluded. Therefore, the outer diameter of the shaft or the holder becomes small. Thus, the rigidity of the shaft or the holder is lowered, and natural vibration of the bobbin holder occurs in the operational range of the bobbin holder. Accordingly, as illustrated in Fig. 8, the vibration becomes large at the operational range above 10,000 rpm. As a result, there is a problem in that the bobbin holder cannot be rotated in such a high operational range. Accordingly, the winding machine cannot be operated at a high speed. DE-A-30 44 315 discloses a bobbin holder as set out in the preamble of claim 1. Said bobbin holder comprises a cylindrical sleeve slideably supported on a supporting shaft of the bobbin holder. The sleeve is provided with concaves and a part of each chucking member is received within the respective concave. For expanding the chucking members radially outwardly or for moving the chucking members radially inwardly, said sleeve is displaced axially on the supporting shaft. Objects of the Invention It is an object of the present invention to provide a bobbin holder which can have a small diameter and a long length and which at the same time shows a reduced tendency to develop vibration so that said bobbin holder can be operated at a high speed. SUMMARY OF THE INVENTION According to the present invention, the above described object is achieved by means of a bobbin holder that comprises the features set out in claim 1. According to the present invention, the portions around the supporting shaft for disposing the chucking member, i.e., the portions on the supporting shaft itself or the portions on the holder integrally inserted onto the supporting shaft, are formed in a concave and a part of the chucking members is inserted into the concave. When the thickness of the chucking member is unchanged, the outer diameter of the shaft or the holder can be increased compared with that applied to a conventional bobbin holder. Accordingly, the rigidity of the shaft or the holder is enhanced. As a result, the natural frequency of the bobbin holder becomes high, and the operational speed of a bobbin holder having a small outer diameter and a long length can be increased. The degree of improvement of the natural frequency relative to a conventional apparatus increases as the ratio between the concave and the length of the bobbin holder decreases. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be explained in detail referring to the attached drawings wherein: Fig. 1 is a cross sectional view of an embodiment of a bobbin holder according to the present invention; Fig. 2 is a cross sectional view taken along line B-B in Fig. 1; Fig. 3 is a detailed view of portion A in Fig. 1; Fig. 4 is a developed view seen in arrow C in Fig. 3; Fig. 5 is a detailed view of another embodiment corresponding to portion A; Fig. 6 is a developed view seen in arrow D in Fig. 5; Fig. 7 is a diagram showing vibration of a holder when a bobbin holder according to the embodiment illustrated in Fig. 1 is rotated; Fig. 8 is a diagram showing vibration of a holder when a bobbin holder according to the conventional technology is rotated; and Fig. 9 is a detailed view of a still other embodiment corresponding to portion A. DESCRIPTION OF PREFERRED EMBODIMENTS Referring to Fig. 1 illustrating a cross sectional view of an embodiment of a bobbin holder according to the present invention, a tapered portion 1a formed at the right end of a hollow supporting shaft 1 engages with a frame 18 of a winding machine and is supported by the latter. Reference numeral 23 denotes a nut, the tapered portion 1a of the supporting shaft 1 is fixedly secured to the frame 18 by threading the nut 23. A shaft 2 is coaxially supported in the hollow portion of the supporting shaft 1 by means of bearings 4 and 5 and is rotatable relative to the supporting shaft 1. Reference numeral 16 denotes a stop ring of the bearing 4. The longitudinal center 2a of the shaft 2 engages with an aperture formed in a holder 3 providing an interference between the shaft 2 and the holder 3, and the shaft 2 and holder 3 are integrally secured by means of a nut 17. The shaft 2 has a longitudinal hole 2b coaxially formed at the axial center thereof, and compressed air is supplied from the rear portion of the shaft 2 through the longitudinal hole 2b when a bobbin is disengaged. The holder 3 formed in a cylindrical shape is secured to the longitudinal center 2a of the shaft 2 as described above. The holder 3 has a plurality of concaves 3a-3l formed at the outer surface thereof spacing in the lengthwise direction of the holder 3. Each of the concaves 3a-3l circumferentially encircles the periphery of the holder 3 as illustrated in Fig. 2. As illustrated in Fig. 3, channels 3m are formed at the outer surface of the holder 3 at portions axially adjacent to the concaves 3a-3l. A cap 6 is secured to the front end of the holder 3 by means of bolts 19 so that a cylinder chamber E is formed. A piston is sealingly and slidably fitted to the front end of the shaft 2 via an O-ring 20. An O-ring 21 is engaged into an O-ring engaging groove 7a formed at the outer surface of the piston 7. Thus, the piston 7 is slidably and sealingly engaging with a cavity formed at the front end of the holder 3 via the O-ring 21. A spring 8 is disposed between the front end of the holder 3 and the piston 7 so that the piston 7 is urged to the left in Fig. 1. Three pins 9 equidistantly spaced around the peripheral surface of the piston 7 are screw threaded to the surface of the piston 7. The pins 9 penetrate the holes 3n which are elongated in an axial direction and which are formed in the holder 3 and engage with the holes 10c formed in a sleeve 10A. The sleeve 10A slidably engages with the outer peripheral surface of the holder 3 and has the above-described three holes 10c equidistantly formed around the periphery thereof. Subsequent to the above-described sleeve 10A, cylindrical sleeves 10B, 10C, 10D, 10E, 10F, 10G, 10H 10I, 10J, 10K, and 10L are successively and slidably inserted onto the holder 3 so that they axially align. Chucking members 12A-12L which engage and disengage bobbins are disposed in the above-described concaves 3a-3l. In the following description, the sleeves 10A-10L are merely referred to as "sleeve 10". Reference numeral 10b denotes a notch which is formed in the sleeve 10 in such a manner that it is perpendicular to a notch 10a forming a T shape. When the bobbin 22 is disengaged, the notch 10b engages with the projections 14c and 14d formed on the tapered member 14 so that the tapered member 14 is moved to the right in Fig. 1. The construction of the chucking members 12A, 12B, 12C, 12D, 12E, 12F, 12G, 12H, 12I, 12J, 12K and 12L will now be explained referring to Figs. 3 and 4. A chuck 13 has an outer surface 13b for engaging with and holding the inner surface of the bobbin 22. The tapered surface 13a formed in the inner surface of the chuck 13 engages with the tapered surface 14b of the tapered member 14 and radially expands the chuck 13. Then, the outer surface 13b of the chuck engages with the inner surface of the bobbin 22 and holds the bobbin 22. In Fig. 3, a hook 13c is formed at the left end of the chuck 13, and the hook 13c engages with the groove 3m formed near the concaves 3a-3l of the holder 3. The tapered members 14 are disposed in the annular concaves 3a-3l which are formed in the holder 3, and springs 15 are fitted to pins 14a projecting from the right end of the tapered members 14 so that the tapered members 14 are moved to the left in Figs. 1 and 3 by means of the spring 15 and expand the chucks 13. In Fig. 4, reference numeral 10a denotes a notch formed in the sleeve 10 and extending in an axial direction of the sleeve 10. The chuck 13 projects through the notch 10a. In the present embodiment, six chucks 13 are assigned to each of the annular concaves 3a-3l, and the notches 10a are formed in such a manner that they equidistantly divide the outer periphery of the respective sleeve 10. Further, reference numeral 13d and 13e denote projections formed at the sides of the chuck 13, and the projections 13d and 13e engage with the inner side of the sleeve 10 so that they prevent the tapered member 14 from projecting beyond the predetermined amount. The operation of the bobbin holder which has the above-described construction will now explained. Engagement of Bobbin The compressed air in the cylinder chamber E is exhausted, and the piston 7 is moved to the left in Fig. 1 by means of the spring 8. Accordingly, the sleeve 10A is moved to the left so that the engagement between each sleeves 10A-10L and the respective projection 14c and 14d of the tapered member 14 is disengaged, i.e., the tapered member 14 becomes free from the sleeve 10. Under this condition, then, the tapered member 14 is moved to the left in Fig. 1 by means of the spring 15, and the tapered surface 14b engages with the tapered portion 13a of the chuck 13 so that the chuck 13 is expanded outwardly. As a result, the chuck 13 holds the inner side of the bobbin 22. Disengagement of Bobbin A compressed air supplying nozzle (not shown) is pressed to the rear end, i.e., the right end in Fig. 1, of the shaft 2, and compressed air is supplied to the cylinder chamber E through the hole 2b formed in the shaft 2 so that the piston 7 is moved to the right in Fig. 1. Due to the movement of the piston 7, the sleeves 10A-10L are moved to the right via the pin 9. Thus, the notches 10b formed in the respective sleeve 10 engage with the projections 14c and 14d of the tapered member 14, and the tapered member 14 is moved to the right in Figs. 1, 3 and 4 against the force of the spring 15. As described above, the tapered member 14 moves to the right in Fig. 1 against the force of the spring 15, and the the engaging portion, i.e., the tapered surface 13a, slides relative to the tapered member 14, and the chuck 13 is radially contracted. According to the present embodiment, the portions around the supporting shaft for disposing the chucking member are formed in a concave and a part of the chucking members is inserted into the concave. Thus, the outer diameter of the shaft or the holder can be increased and the rigidity of the shaft or the holder is enhanced. The rigidity could be enhanced to about 1.5 times (if some designs are altered, between 1.4 and 1.7 times) as much as that obtained by a conventional apparatus without chucking member disposing concave. As a result, the natural frequency of the bobbin holder becomes high, and the figure relating to the vibration, such as amplitude, at a high operational speed can be low though a bobbin holder having a small outer diameter and a long length is used. When six bobbins having an inner diameter of 94mm are held (the total length of 1,200mm), the apparatus of the present embodiment was substantially free from a large vibration below 15,000 rpm as illustrated in Fig. 7, while the vibration remarkably increased at an operational range beyond about 10,000 rpm in a conventional apparatus as illustrated in Fig. 8. Although the sleeves inserted onto the holder are not connected to each other in an axial direction in the above-described embodiment, they may be connected to each other for example by means of suitable engaging members, such as projections. Although the concaves were formed in the holder which is supported on the supporting shaft in the above-described embodiment, the concaves may be formed on the supporting shaft when the present invention is carried out in an apparatus wherein a holder is not used and the chucking members are directly inserted onto the supporting shaft. Another embodiment is illustrated in Figs. 5 and 6. Although the springs 15 are fitted to the pins 14a projecting from the tapered portion 14 in the above-described embodiment, the tapered member 14 has an cavity 14a' formed therein in this embodiment, and a spring 15 is fitted in the cavity 14a'. According to the present invention, springs may be engaged with the sleeves 10b-10l or only the sleeve 11 so that the sleeves 10b-10l are moved to the left by the spring force when the bobbins are disengaged. Although the sleeves are pressed from the front end of the holder when the bobbins are disengaged in the above-described embodiments, the chucking members may be arranged in such a manner that they are pressed from the rear end by an actuator disposed at the rear end of the holder or the outside of the holder. A detailed view of a portion corresponding to portion A in a further embodiment is illustrated in Fig. 9. According to the present invention, a tapered portion 103a may be formed on a concave groove 103b of a holder 103, and a tapered portion 113a of a chuck 113 may be engaged with the tapered portion 103a. Reference numeral 115 denotes a spring disposed at a space 103a between the holder 103 and the chuck 113 to urge the chuck 113. According to the present invention, the portions around the supporting shaft for disposing the chucking member are formed in a concave and a part of the chucking members is inserted into the concave. Thus, the outer diameter of the shaft or the holder can be increased and the rigidity of the shaft or the holder can be enhanced. According to the present invention, the rigidity can be remarkably enhanced compared with a conventional apparatus without portions in the supporting shaft for disposing the chucking member. As a result, the natural frequency of the bobbin holder becomes high, and the figure relating to the vibration, such as amplitude, at a high operational speed can be low though a bobbin holder having a small outer diameter and a long length is used.

Claims: A bobbin holder for mounting on a yarn winding machine, which bobbin holder comprises a supporting shaft (1), a plurality of chucking members (12A - 12L) disposed at an outer periphery of the supporting shaft (1), said chucking members (12A - 12L) being adapted to expand radially outwardly upon being compressed longitudinally so as to chuck an inner side of a cylindrical bobbin (22) coaxially inserted onto the supporting shaft (1), and to move radially inwardly so as to release said bobbin (22), wherein concaves (3a - 3l) are provided around the supporting shaft (1) with a part of said chucking members (12A - 12L) being received into said concaves (3a - 3l), characterized in that said concaves (3a - 3l) are either formed on the supporting shaft (1) itself or on a cylindrical holder (3) mounted directly onto the supporting shaft (1) and secured in an axially non-displaceable manner with regard to the supporting shaft. A bobbin holder according to claim 1, characterized in that said holder (3) further comprises, at the outer surface thereof, channels (3m) formed at portions axially adjacent to the concaves (3a - 3l), and said chucking members (12A - 12L) have hooks (13c) engaging said channels (3m). A bobbin holder according to claim 1 or 2, characterized in that a plurality of said concaves (3a - 3l), each of which extends in a circular periphery of said supporting shaft (1), are spaced in an axial direction of said supporting shaft (1). A bobbin holder according to one of claims 1 to 3, characterized in that said chucking members (12A - 12L) are caused to expand radially outwardly or to move radially inwardly by means of sleeves (10A - 10L) that are inserted onto the holder (3) or the supporting shaft (1) and that are axially displaceable with regard to the holder (3) or the supporting shaft (1), respectively.

Inventors: ISHIMARU NORIKI, SUGIOKA TAKAMI, ISHIMARU, NORIKI, SUGIOKA, TAKAMI, ISHIMARU, NORIKI, C/O TEIJIN SEIKI CO.,LTD., SUGIOKA, TAKAMI, C/O TEIJIN SEIKI CO.,LTD.
Applicants: TEIJIN SEIKI CO LTD, TEIJIN SEIKI CO. LTD.
Application year: 1994
Main classification: B65H54
IPC codes: B65H54